/ Design and geometry of climbing frame/fork

I would appreciate feedback from dedicated cycling hill climb riders,experienced bike designers and manufacturers and hopefully from custom bike frame builders:
Which frame and fork characteristics do you recommend for a dedicated climbing bike in regards to Front/Rear- BB distances;chain stay length; total wheelbase; seat and head tube angles, BB drop, fork rake and overall trail measurements.The climbs are both long and steep and will require a quick-response bike, with accelerations while climbing .
As I will have a frame custom made, there is no need to promote any brand or make/model, but if you have specific recommendations,please base them on a 58cm frame for reference.
Thank you for any advice and input.

The frame needs to be stiff torsionally, meaning as little "twist" as possible along the length of the bike so that your pedal input goes straight to the rear wheel. The wheels need to be stiff and strong. A standard fork is fine; Ive never heard of a climbing fork.

As the owner of a 2006 Roubaix and a 2013 Roubaix I can tell you that carbon bike frame technology is moving ahead fast; there is a massive improvement in the stiffness, efficiency and comfort of the newer frame. My advice to you would be to buy a modern carbon bike and get out and ride it because I think metals are being left behind.

Is this bike purely been used for hill climbs or do you want it to be used as an all rounder? As if you are starting purely from scratch you could design something for build on the edges of the standard types of roadbike that could only be used for one discipline which is going up hills quickly, take a track bike as an example, a very fast bike, which you may have problems with on a sunday club run.

Thanks all for responses.
It will be a dedicated climbing bike - no all-rounder for club rides.
As only climbing geometry and frame/fork design are of interest at this point,frame material, wheels and components are not the focus.
Custom carbon is likely the choice, however.

In reply to ablackett:
Apropiate question and very valid comment,as I understand that fixies and track bikes are sometimes used for hill climbs.
Whereas I need a geared hill climb bike,it would be very interesting to learn from riders of fixies/track bikes about their experiences as compared to using more regular road bikes.

Hello again this is quite a big subject, so without getting too involved. I think if I had to put together a similar bike for myself, knowing how expensive custom builds can be, I wouldn't want a dud! So I'd give a big hi five to the R & D boys at all the fine bike companies and have a good look at all the numbers and angles that they publish and try and work out how they relate to me and how I climb then I'd go to this website and with my first set of derived values and build an initial model.

In reply to anatso: my hill climb specific bike was a track bike, built up ultra light, with a fixed gear. I don't knew what sort of events exactly you are planning on doing, but for the vast majority of hill climbs in the UK I wouldn't even contemplate riding gears. A fixed wheel carries you through the dead spot far better than I found gears ever could. In terms if specific geometry, I'm not sure exactly what you're hoping for. I always found a track frame fine. I did stick super expensive tubs on for national champs, and carbon fibre saddle, chopped off bars, and spent many an evening weighing brakes and brake levers, wheels etc, working out where I could save a bit more weight! Lots of fun to be had, that's for sure, though at the end of the day, the best riders are still the best riders, regardless of what bike they're on! Lance was right about that - it's not about the bike!

In reply to rmt:
Thanks again for interesting feedback.
It sounds like a track bike geometry is a good starting point; and this will serve to narrow down frame parameters.The fixie part may become a practical challenge with the variety of hill climb profiles planned for, but not to be dismissed.

In reply to anatso: Can you clarify, unless I have missed it, do you mean hill climb bike as in the sport of hill climbs in the late part of the season normally only seen in the UK or do you mean 20k alpine cols ?

If its the former you could do worse than do a search on Jack Pullar who is the reigning national hill climb champion, there was some articles on his bike in the mags, weight was first on the list, there was never any mention of geometry.

If it's the latter then any road bike with race geometry will work.

I am struggling to see any benefits in a bike with custom geometry over an off the shelf bike with race geometry for either option though.

I think many people use track bikes for hill climbs because they are light and simple, but I question the wisdom of real track frame geometry. For example, I would not think that a high bottom bracket combined with short cranks (standard for many track bikes) would be appropriate for climbing. I think a lower bottom bracket combined with longer cranks would make more sense, especially when standing on the pedals (less teeter/totter).

I would also ask myself: how do I climb? Do you slide back in the saddle and push the pedals from behind? Then get a bike with a more slack seat tube, like a sport touring bike. Do you pull yourself forward on the saddle and push the pedals from above? Then get a bike with a more upright seat tube, like a criterium or triathlon bike. Do you move back and forth a great deal? Then get a bike with a regular seat tube angle, like a standard road racing bike.

Then I would think about the handlebars. Sitting a little more upright, as opposed to being really stretched out and low, seems more appropriate for steep climbing, so I would make sure that the top tube was perhaps a little shorter than normal, and I would have the top tube slope upwards a little more than normal, to bring the handlebars closer and higher, without having to add spacers under the stem.

To combat the feeling of tipping backwards or doing a wheelie, I might think about chain stays a little longer than normal.

And I would say you would probably want a pretty stable steering bike, not too quick and twitchy, so something with trail on the longer side of normal.

> (In reply to brunoschull)
>
> You may or not may not be aware of the UK Hill Climb race scene - I'm guessing your US based.
>
> They are short time trial races on very steep hills - often only lasting a few minutes.
>
> Think a 3 minute blast up a 25% hill.

Exactly.
So you should be looking at: (a) what's your best effective stack/reach combination (assuming a 20% slope, say) to generate the maximum power out of the saddle over ~ 3 mins, (b) reasonable stability so you go up the slope rather than weave (particularly when completely knackered) and (c) ensuring adequate rear wheel traction (bad, wet surfaces seem common).

In reply to Marek:
Thanks for further feedback; and, indeed, the goal is to zero in on the most most proficient stack/reach parameters and trail measurements for racing hill climbs,with consideration for climbing style.Lots of good ideas.
I am familiar with the UK series; I got my introduction to bike racing in Coventry. I am currently based in the US/Canada, but will also spend racing time in the UK, which means both short and steep climbs, as well as long and gradual.
Custom carbon is available from several NA builders using Enve (Utah, US)tubes, for example, but the purpose of my post is to encourage wide-ranging input from existing knowledge base in the cycling community.

Yes, as one post above noted, my background is in the US, where hill climb time trials range in length/steepness/time, and my thoughts were directed at a range of climbing scenarios, not just a full out of saddle two minute effort. My impression (which appears to be accurate) was that the original post asked about a versatile climbing bike, not something only lasting a few minutes, therefore, my advice was aimed in that direction.

Nonetheless, even for short out-of-saddle efforts, I largely stand by my original post. The whole issue of crank length/cadence is not so easy as long cranks=low cadence and short cranks=high cadence. Consider that if you are riding a certain gear at a certain speed, your cadence will be the same regardless of your crank length. With cranks of different length the bio-mechanics and forces your legs and muscles may be different, but it does not necessarily effect cadence. That may be self-evident, but the post above appears to confuse the issue. Or consider how people always talk about long cranks for low cadence or "slow twitch" efforts, and short cranks are for high cadence or "fast twitch" efforts. Beside vastly oversimplifying the physiology of performance, it stands to reason that, for a certain gear and speed, with longer cranks a cyclist's feet will actually be traveling faster than with shorter cranks (same time to complete the circle, but larger diameter). In any case, for out of the saddle efforts, a lower bottom bracket and longer cranks will almost certainly feel more stable and powerful than a high bottom bracket and shorter cranks for most riders. Remember, we are not talking about the velodrome, flat road sprints, or flat time trialing, with cadences well over 100 RPM. If were are truly taking about steep climbs, then they will be a grind.

Regarding seat tube angle/chain stay length/tire clearance...I think it's primarily a balance and stability issue, not a stiffness issue. It doesn't matter how short and stiff the chainstays are, nor how effectively the frame "transmits torque to the rear wheel" (probably the most overused statement in the bike industry). If the back wheel does not stay on the ground, then you are not moving forward effectively. Having the rear wheel skip while standing up and sprinting on a climb is a real problem, and I don't think the solution is necessarily tucking the rear wheel as closely against the seat tube as possible. It might look cool, and seem fast, but in practice I remain skeptical. I think a balanced bike with more normal geometry (which has been refined for over 100 years) will be faster on the climbs.

One thing I'll add, just to play the devil's advocate, if we are talking about short out of saddle climbs (even though that is not what the original post suggested) I would go for a bar on the wide side of normal. A wider bar will provide more leverage.